Wednesday, 6 October 2010

Rotogravure (Rotary Printing - Gravure - Intaglio)

Gravure printing is characteristically used for long run, high quality printing producing a sharp, fine image.
Typical gravure printed products include:
Food packaging
Wall paper
Wrapping paper
Furniture laminates
Greeting cards

Gravure printing is an example of intaglio printing.
A rotogravure printing press has one printing unit for each colour, typically CMYK or cyan, magenta, yellow and key (printing terminology for black). The number of units varies depending on what colors are required to produce the final image. There are five basic components in each color unit: an engraved cylinder (AKA "Gravure cylinder") (whose circumference can change according to the layout of the job), an ink fountain, a doctor blade, an impression roller, and a dryer. While the press is in operation, the engraved cylinder is partially immersed in the ink fountain, filling the recessed cells. As the cylinder rotates, it draws ink out of the fountain with it. Acting as a squeegee, the doctor blade scrapes the cylinder before it makes contact with the paper, removing ink from the non-printing (non-recessed) areas. Next, the paper gets sandwiched between the impression roller and the gravure cylinder. This is where the ink gets transferred from the recessed cells to the paper. The purpose of the impression roller is to apply force, pressing the paper onto the gravure cylinder, ensuring even and maximum coverage of the ink. Then the paper goes through a dryer because it must be completely dry before going through the next color unit and absorbing another coat of ink.

Web-fed gravure presses account for almost all publication, packaging, and product gravure printing. These presses are generally custom manufactured machines designed for a specific range of products. The typical press is highly automated and consists of multiple print units. The printing mechanism in a rotogravure press consists of a gravure cylinder and a smaller, rubber clad impression cylinder.

Other types of gravure presses in commercial use today are sheet-fed, intaglio plate, and offset gravure. These types of presses are used primarily for special printing applications.

Examples of Gravure:

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